<ul>
{volist name="arr" id="li"}
    <li>{if condition="$li['id'] eq 1"}第一个{/if}-{$li.id}-{$li.name}</li>
{/volist}
    <form action="/index/b" method="post">
        <input type="text" name="username">
        <input type="password" name="password">
        <button type="submit">登录</button>
    </form>
</ul>